1 files changed, 214 insertions, 0 deletions
diff --git a/src/os/events_windows.c b/src/os/events_windows.c
new file mode 100644
index 0000000..f22bebc
--- /dev/null
+++ b/src/os/events_windows.c
@@ -0,0 +1,214 @@
+/*
+ * libusb event abstraction on Microsoft Windows
+ *
+ * Copyright © 2020 Chris Dickens <christopher.a.dickens@gmail.com>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include <config.h>
+
+#include "libusbi.h"
+#include "windows_common.h"
+
+int usbi_create_event(usbi_event_t *event)
+{
+	event->hEvent = CreateEvent(NULL, TRUE, FALSE, NULL);
+	if (event->hEvent == NULL) {
+		usbi_err(NULL, "CreateEvent failed: %s", windows_error_str(0));
+		return LIBUSB_ERROR_OTHER;
+	}
+
+	return 0;
+}
+
+void usbi_destroy_event(usbi_event_t *event)
+{
+	if (!CloseHandle(event->hEvent))
+		usbi_warn(NULL, "CloseHandle failed: %s", windows_error_str(0));
+}
+
+void usbi_signal_event(usbi_event_t *event)
+{
+	if (!SetEvent(event->hEvent))
+		usbi_warn(NULL, "SetEvent failed: %s", windows_error_str(0));
+}
+
+void usbi_clear_event(usbi_event_t *event)
+{
+	if (!ResetEvent(event->hEvent))
+		usbi_warn(NULL, "ResetEvent failed: %s", windows_error_str(0));
+}
+
+#ifdef HAVE_OS_TIMER
+int usbi_create_timer(usbi_timer_t *timer)
+{
+	timer->hTimer = CreateWaitableTimer(NULL, TRUE, NULL);
+	if (timer->hTimer == NULL) {
+		usbi_warn(NULL, "CreateWaitableTimer failed: %s", windows_error_str(0));
+		return LIBUSB_ERROR_OTHER;
+	}
+
+	return 0;
+}
+
+void usbi_destroy_timer(usbi_timer_t *timer)
+{
+	if (!CloseHandle(timer->hTimer))
+		usbi_warn(NULL, "CloseHandle failed: %s", windows_error_str(0));
+}
+
+int usbi_arm_timer(usbi_timer_t *timer, const struct timespec *timeout)
+{
+	struct timespec systime, remaining;
+	FILETIME filetime;
+	LARGE_INTEGER dueTime;
+
+	/* Transfer timeouts are based on the monotonic clock and the waitable
+	 * timers on the system clock. This requires a conversion between the
+	 * two, so we calculate the remaining time relative to the monotonic
+	 * clock and calculate an absolute system time for the timer expiration.
+	 * Note that if the timeout has already passed, the remaining time will
+	 * be negative and thus an absolute system time in the past will be set.
+	 * This works just as intended because the timer becomes signalled
+	 * immediately. */
+	usbi_get_monotonic_time(&systime);
+
+	TIMESPEC_SUB(timeout, &systime, &remaining);
+
+	GetSystemTimeAsFileTime(&filetime);
+	dueTime.LowPart = filetime.dwLowDateTime;
+	dueTime.HighPart = filetime.dwHighDateTime;
+	dueTime.QuadPart += (remaining.tv_sec * 10000000LL) + (remaining.tv_nsec / 100LL);
+
+	if (!SetWaitableTimer(timer->hTimer, &dueTime, 0, NULL, NULL, FALSE)) {
+		usbi_warn(NULL, "SetWaitableTimer failed: %s", windows_error_str(0));
+		return LIBUSB_ERROR_OTHER;
+	}
+
+	return 0;
+}
+
+int usbi_disarm_timer(usbi_timer_t *timer)
+{
+	LARGE_INTEGER dueTime;
+
+	/* A manual-reset waitable timer will stay in the signalled state until
+	 * another call to SetWaitableTimer() is made. It is possible that the
+	 * timer has already expired by the time we come in to disarm it, so to
+	 * be entirely sure the timer is disarmed and not in the signalled state,
+	 * we will set it with an impossibly large expiration and immediately
+	 * cancel. */
+	dueTime.QuadPart = LLONG_MAX;
+	if (!SetWaitableTimer(timer->hTimer, &dueTime, 0, NULL, NULL, FALSE)) {
+		usbi_warn(NULL, "SetWaitableTimer failed: %s", windows_error_str(0));
+		return LIBUSB_ERROR_OTHER;
+	}
+
+	if (!CancelWaitableTimer(timer->hTimer)) {
+		usbi_warn(NULL, "SetWaitableTimer failed: %s", windows_error_str(0));
+		return LIBUSB_ERROR_OTHER;
+	}
+
+	return 0;
+}
+#endif
+
+int usbi_alloc_event_data(struct libusb_context *ctx)
+{
+	struct usbi_event_source *ievent_source;
+	HANDLE *handles;
+	size_t i = 0;
+
+	/* Event sources are only added during usbi_io_init(). We should not
+	 * be running this function again if the event data has already been
+	 * allocated. */
+	if (ctx->event_data) {
+		usbi_warn(ctx, "program assertion failed - event data already allocated");
+		return LIBUSB_ERROR_OTHER;
+	}
+
+	ctx->event_data_cnt = 0;
+	for_each_event_source(ctx, ievent_source)
+		ctx->event_data_cnt++;
+
+	/* We only expect up to two HANDLEs to wait on, one for the internal
+	 * signalling event and the other for the timer. */
+	if (ctx->event_data_cnt != 1 && ctx->event_data_cnt != 2) {
+		usbi_err(ctx, "program assertion failed - expected exactly 1 or 2 HANDLEs");
+		return LIBUSB_ERROR_OTHER;
+	}
+
+	handles = calloc(ctx->event_data_cnt, sizeof(HANDLE));
+	if (!handles)
+		return LIBUSB_ERROR_NO_MEM;
+
+	for_each_event_source(ctx, ievent_source) {
+		handles[i] = ievent_source->data.os_handle;
+		i++;
+	}
+
+	ctx->event_data = handles;
+	return 0;
+}
+
+int usbi_wait_for_events(struct libusb_context *ctx,
+	struct usbi_reported_events *reported_events, int timeout_ms)
+{
+	HANDLE *handles = ctx->event_data;
+	DWORD num_handles = (DWORD)ctx->event_data_cnt;
+	DWORD result;
+
+	usbi_dbg(ctx, "WaitForMultipleObjects() for %lu HANDLEs with timeout in %dms", ULONG_CAST(num_handles), timeout_ms);
+	result = WaitForMultipleObjects(num_handles, handles, FALSE, (DWORD)timeout_ms);
+	usbi_dbg(ctx, "WaitForMultipleObjects() returned %lu", ULONG_CAST(result));
+	if (result == WAIT_TIMEOUT) {
+		if (usbi_using_timer(ctx))
+			goto done;
+		return LIBUSB_ERROR_TIMEOUT;
+	} else if (result == WAIT_FAILED) {
+		usbi_err(ctx, "WaitForMultipleObjects() failed: %s", windows_error_str(0));
+		return LIBUSB_ERROR_IO;
+	}
+
+	result -= WAIT_OBJECT_0;
+
+	/* handles[0] is always the internal signalling event */
+	if (result == 0)
+		reported_events->event_triggered = 1;
+	else
+		reported_events->event_triggered = 0;
+
+#ifdef HAVE_OS_TIMER
+	/* on timer configurations, handles[1] is the timer */
+	if (usbi_using_timer(ctx)) {
+		/* The WaitForMultipleObjects() function reports the index of
+		 * the first object that became signalled. If the internal
+		 * signalling event was reported, we need to also check and
+		 * report whether the timer is in the signalled state. */
+		if (result == 1 || WaitForSingleObject(handles[1], 0) == WAIT_OBJECT_0)
+			reported_events->timer_triggered = 1;
+		else
+			reported_events->timer_triggered = 0;
+	} else {
+		reported_events->timer_triggered = 0;
+	}
+#endif
+
+done:
+	/* no events are ever reported to the backend */
+	reported_events->num_ready = 0;
+	return LIBUSB_SUCCESS;
+}